Continuous fiber tennis racquet

ABSTRACT

A tennis racquet composed entirely, except for the strings and a leather handle cover, of resin impregnated glass fibres approximately 25 percent of which extend unbrokenly up one handle, around the bow including the throat, around the head and down the other handle, approximately 50 percent of which extend up one handle around the head and then down the other handle, and approximately 25 percent of which extend up one handle member, across the throat and then down the other handle member. Short fibres are positioned across the throat to make the throat contain a number of fibres equal to that of any other portion of the racquet.

H110 Johns States Patent 1191 1 1 CONTINUOUS FIBER TENNIS RACQUET [22] Filed: Aug. 28, I970 21 App1.No.: 67,882

[52] US. Cl 2 73/73 F, 273/D1G. 7 [51] Int. Cl A63b 49/10 [58] Field of Search 273/67 R, 73, DIG. 7; 124/23 [56] References Cited UNITED STATES PATENTS 2,980,158 4/1961 Meyer 273/73 F 3,483,055 12/1969 Eshbaugh 273/73 F X 2,878,020 3/1959 Robinson 273/73 F 2,980,158 4/1961 Meyer 273/73 F FOREIGN PATENTS OR APPLICATIONS 577,560 6/1924 France 273/73 F 962,312 12/1949 France 273/73 K 1,310,470 10/1962 Francelm, 273/73 D 307,157 3/1929 Great Britain 273/73 K 255,039 10/1927 Italy 273/73 K 848,826 8/1970 Canada 273/73 F 17,462 5/1934 Australia 273/73 F AWFQ'G/Vflfffi 50 FEE/Q5 Jan. 22, 1974 Primary Examiner-Richard C. Pinkham Assistant Examiner Richard J. Apley Attorney, Agent, or Firm-Lyon & Lyon [57] ABSTRACT A tennis racquet composed entirely, except for the strings and a leather handle cover, of resin impregnated glass fibres approximately 25 percent of which extend unbrokenly up one handle, around the bow including the throat, around the head and down the other handle, approximately 50 percent of which extend up one handle around the head and then down the other handle, and approximately 25 percent of which extend up one handle member, across the throat and then down the other handle member. Short fibres are positioned across the throat to make the throat contain a number of fibres equal to that of any other portion of the racquet.

3 Claims, 8 Drawing Figures CONTINUOUS FIBER TENNIS RACQUET INTRODUCTION This invention relates to a tennis racquet and more particularly to such a racquet the body of which is composed entirely of glass fibres impregnated with a thermosetting resin. For improved strength it is desirable to form the racquet, so far as it is possible, of continuous unbroken fibres. However, due to the peculiar shape of a tennis racquet it is not possible to achieve this ideal. Hence this invention is in essence an attempt to use in the structure of a racquet as many continuous unbroken fibres as possible and yet still make a balanced racquet having a uniform cross-section in all parts of the bow, even including the throat.

This object and others will be apparent from the following description in which:

FIG. 1 is a plan view of a pair of molds suitable for making the racquet of this invention, the molds being shown in their open position.

FIG. 2 is a fragmentary cross-section taken along line 2-2 of FIG. 1.

FIG. 3 is a view similar to 'FIG. 2, but showing the mold filled and closed.

FIGS. 4-6 is a diagram of the position in which approximately 50 percent of the glass fibres are laid in the mold.

FIGS. 5-7 is a diagram of the position in which approximately 25 percent of the glass fibres are laid in the mold.

FIG. 8 is a diagram of the position in which approximately 25 percent of the glass fibres are laid in the mold.

Referring now more particularly to the drawings, FIG. 1 illustrates a mold formed in two halves l0 and 11 hinged together by a hinge 12. Each half 10 and 11 is provided with a groove 13 or 14 which grooves trace the outline of a tennis racquet frame. That is to say, each groove has a head portion 15, a throat portion 16 and two handle portions 17 and 18.

As known in the art, glass fibers are arranged with about 204 unidirectionally extending filaments in a unit known as a sliver. The term E glass designates the composition and stands for electrical" versus chemical". The term K represents a filament-diameter of about 0.00055 inch. (See Handbook of Reinforced plastics of the SP1, Oleesky and Mohr, pub. 1964 by Reinhold Pub. Corp, pp 117-166).

Glass fibres impregnated with a flexible epoxy resin of the amine type and B staged to a semicured state are laid in the grooves 13 and 1-4 in the following manner:

Bundles of E glass fibres of the K fibre diameter are used with approximately 60 slivers to the bundle. The first step comprises laying 50 bundles into the molds in the pattern shown in FIGS. 4-6, that is to say, up one handle, around the headand down the other handle. The second step comprises laying bundles into the molds in the pattern shown in FIGS. 5-7, that is to say, up one handle, completely around the bow, around the head and then down the other handle. The third step comprises laying into the molds 50 bundles in the pattern shown in FIG. 8, that is to say, up one handle, across the throat and down the other handle. Concurrently short bundles are laid across the throat only. The fourth step comprises a repeat of the second step; i.e., an additional 25 fibres are laid in the pattern of FIGS. 5-7. The fifth step is a repeat of the first step; i.e., another 50 bundles are laid in the pattern of FIGS. 4-6. This process is continued until both molds l3 and 14 are filled. The molds are then closed and the material in the molds is cured, preferably by energizing the heating elements 20 and 21 and curing the racquet for 30 minutes at 200-225 F.

After curing the racquet is removed from the molds and is complete except for fitting a handle to the two handle portions formed in portions 17 and 18 of the mold, boring the holes in the head of the racquet and stringing.

The term glass" as used herein is defined as fibre glass, or alternately any of the commercially available materials generally described as carbon graphite Boron high modulus glass, or any mixture of the former with the latter.

While there has been disclosed what at present is considered a preferred embodiment of the present invention it will be appreciated that various changes and modifications may be made therein without departing from the essence of the invention.

What is claimed is:

1. In a tennis racquet frame composed entirely of resin impregnated continuous unidirectional reinforcing fibers and having spaced handle portions joined to a head bow and a throat portion extending between said handle portions to complete, with said head bow, a closed head loop, the improvement comprising:

a first plurality of continuous unbroken fibers extending along one handle portion, around said head bow, along said throat portion, around said head bow again, and then along said other handle portion; and

a second plurality of unbroken continuous fibers extending along one handle portion, along said throat portion, and along the other handle portion.

2. A tennis racquet as defined in claim 1 including a third plurality of continuous unbroken fibers extending along one handle portion, around said head bow, and then along the other handle portion.

3. A tennis racquet as defined in claim 2 including a fourth plurality of unbroken glass fibers extending along only said throat portion, there being substantially the same number of glass fibers extending along each handle portion, around said head bow, and along said throat portion. 

1. In a tennis racquet frame composed entirely of resin impregnated continuous unidirectional reinforcing fibers and having spaced handle portions joined to a head bow and a throat portion extending between said handle portions to complete, with said head bow, a closed head loop, the improvement comprising: a first plurality of continuous unbroken fibers extending along one handle portion, around said head bow, along said throat portion, around said head bow again, and then along said other handle portion; and a second plurality of unbroken continuous fibers extending along one handle portion, along said throat portion, and along the other handle portion.
 2. A tennis racquet as defined in claim 1 including a third plurality of continuous unbroken fibers extending along one handle portion, around said head bow, and then along the other handle portion.
 3. A tennis racquet as defined in claim 2 including a fourth plurality of unbroken glass fibers extending along only said throat portion, there being substantially the same number of glass fibers extending along each handle portion, around said head bow, and along said throat portion. 